Timelapse footage of the flower head of a sunflower Helianthus annuus. The flower of a sunflower is actually a composite of hundreds of small yellow flowers, known as disc florets, arranged in spirals on a flat flower head. The outer petals are sterile flowers called ray florets. This timelapse footage shows that the individual flowers bloom in concentric circles from the outer edge to the centre. The sunflower is native to the Americas, but has been introduced worldwide for its impressive flowers, and edible seeds and oil.